Spin liquid phase for the frustrated Quantum Heisenberg Antiferromagnet on a square lattice

TL;DR

This paper investigates the phase diagram of the frustrated Quantum Heisenberg Antiferromagnet on a square lattice, providing evidence for an intermediate spin liquid phase separating Neel and helicoidal states.

Contribution

It introduces a unified theoretical framework showing the continuous transition and the necessity of a spin liquid phase in the model.

Findings

Existence of a spin liquid phase between Neel and helicoidal states.

Unified action continuous across phase diagram except at Lifshitz point.

Agreement among Spin-Wave, Schwinger Bosons, and hydrodynamic theories.

Abstract

The existance of a spin disordered ground state for the frustrated Quantum Heisenberg Antiferromagnet on a square lattice is reconsidered. It is argued that there is a unique action which is continuous through the whole phase diagram, except at the Lifshitz point, so that the Neel and helicoidal states can not coexist and there has to be an intermediate spin liquid state. To show it, a detailed study combining Spin-Wave theory, Schwinger Bosons Mean Field Theory and a scaling analysis of the appropriate hydrodynamic action is performed. When done carefully, all these theories agree and strongly support the existance of the spin liquThe manuscript has eight figures, which are available upon request to the author. e-mail address is ferrer@physics.rutgers.edu